發(fā)布時間：2017-12-26 22:20

  本文關(guān)鍵詞：X射線光柵相位襯度成像實驗技術(shù)和應(yīng)用研究　出處：《中國科學(xué)技術(shù)大學(xué)》2017年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 光柵相襯成像 實驗技術(shù) 系統(tǒng)優(yōu)化 圖像校正 光柵相襯成像的應(yīng)用

【摘要】：近二十年來,X射線相襯成像得到快速發(fā)展,形成了若干種方法。大部分X射線相襯成像方法需要高空間或時間相干性光源,因此都局限于同步輻射或者微焦點光源。然而,光柵相襯成像能夠使用大功率的常規(guī)X光管作為光源,并且兼容大視場的平板探測器,給X射線相襯成像應(yīng)用于臨床和工業(yè)帶來曙光。另外,光柵相襯成像能同時得到吸收、折射和散射三種相互補充的襯度信息,提供了傳統(tǒng)吸收成像無法探測的信息。經(jīng)過全世界大量科學(xué)家的努力,X射線光柵相襯成像已經(jīng)取得了巨大的發(fā)展,在許多應(yīng)用領(lǐng)域進行了嘗試。特別是在醫(yī)學(xué)成像方面,大量的預(yù)臨床實驗取得了令人鼓舞的結(jié)果,吸引了越來越多科學(xué)界和工業(yè)界的關(guān)注和投入。本論文圍繞光柵相襯成像這一熱點方向,在搭建的光柵相襯成像系統(tǒng)的基礎(chǔ)上,對X射線光柵相襯成像的實驗技術(shù)進行了深入地探索;針對系統(tǒng)出現(xiàn)的問題,對光源、光柵和探測器這些核心部件進行了檢測和優(yōu)化,分析了問題并提出了相應(yīng)的校正和改進方案;通過實際實驗,對光柵相襯成像方法在生物醫(yī)學(xué)成像和食品檢測等應(yīng)用進行了初步探索。這些工作將大大地促進光柵相襯成像技術(shù)的廣泛應(yīng)用。本論文的研究成果歸納如下:1.光柵相襯成像裝置實驗技術(shù):前期完成了基于幾何投影的非相干光柵相襯成像系統(tǒng)的搭建,總結(jié)了一套完整精細(xì)的光柵相襯成像實驗技術(shù)和數(shù)據(jù)處理流程;最后通過性能測試比較本系統(tǒng)和傳統(tǒng)Talbot-Lau干涉儀,指出了本系統(tǒng)的特點。2.X光源的光強偏移現(xiàn)象及校正方法:發(fā)現(xiàn)了提前折射信息錯誤現(xiàn)象,進而分析了光強漂移對實驗結(jié)果的影響。分析光強隨時間的變化的規(guī)律,利用線性的擬合獲得光強的解析表達式,再基于位移曲線提出了一種光強漂移的校正方法,并利用光柵相襯成像實驗驗證了該方法的有效性。3.吸收光柵優(yōu)化放置的成像系統(tǒng):為了減小光柵的熱振動和損傷,基于光柵結(jié)構(gòu)和材料的特點,分析并比較了正入射和背入射兩種光柵放置方案。計算和實驗表明兩種方案在成像結(jié)果上一致,但背入射能減小相應(yīng)的熱效應(yīng)帶來的光柵振動乃至變形,提高系統(tǒng)的穩(wěn)定性,延長光柵使用壽命。4.改進的光柵相襯成像探測器校正方案:為了簡化現(xiàn)有探測器校正過程中的復(fù)雜操作,提出了一種將源光柵和光源作為一個整體參與增益校正的探測器校正方法,并通過實驗驗證了方案的可行性。進一步從理論上分析了暗電流和增益校正對三個信息的影響,提出了一種只需要暗電流校正的光柵相襯成像探測器圖像校正方法。實驗表明新方案和現(xiàn)有方法成像效果一致,并且能大幅度的簡化實驗操作過程,提高工作效率和系統(tǒng)穩(wěn)定性。5.生物醫(yī)學(xué)成像和食品檢測等應(yīng)用探索:提出了一種結(jié)合吸收和折射的新型骨密度測量方案并通過理論計算和實驗得到了驗證;基于鯽魚的光柵相襯成像結(jié)果,發(fā)現(xiàn)并驗證了不同的樣品處理方法對相襯成像實驗結(jié)果的影響;最后,以常見的黃梅干和圣女果作為樣品,探索了相襯成像在食品檢測方面的潛力。
[Abstract]:In the past twenty years, X - ray phase contrast imaging has developed rapidly, and several methods have been formed. Most of the X - ray phase contrast imaging methods require high spatial or temporal coherent light sources, so they are limited to synchrotron radiation or microfocus light sources. However, grating phase contrast imaging can be used as a source of high-power conventional X light source, and compatible with large field of view detector. It brings dawn to X and phase contrast imaging in clinical and industrial applications. In addition, the grating phase contrast imaging can simultaneously obtain three complementary contrast information of absorption, refraction and scattering, which provides information that can not be detected by traditional absorption imaging. Through the efforts of a large number of scientists all over the world, the X - ray grating phase contrast imaging has made great progress and has been tried in many fields of application. In particular, a large number of pre clinical trials have yielded encouraging results in medical imaging, attracting more and more attention and input from the scientific and industrial communities. This paper focuses on grating imaging on this hot topic, based on grating imaging system is built on the in-depth exploration of experimental technology of X X-ray grating imaging; aiming at the problem of the system and the detection and optimization of light source, grating and detector of these core components, analyzes the problems and puts forward the correction and the corresponding improvement scheme; through practical experiments, the method of phase contrast imaging grating in biomedical imaging and food detection and other applications are explored. These work will greatly promote the wide application of grating phase contrast imaging technology. The research results of this thesis are summarized as follows: 1. grating imaging device: the complete set of experimental techniques based on geometrical projection non coherent grating imaging system, summed up a complete set of fine grating imaging technique and data processing; finally, through the comparison of the performance test system and the traditional Talbot-Lau interferometer, pointed out the characteristics of this system. The phenomenon of light intensity migration and correction of 2.X light source: the error of early refraction information is found, and the influence of light intensity drift on the experimental results is analyzed. The rule of light intensity changing with time is analyzed, and the analytical expression of light intensity is obtained by linear fitting. Then a correction method of intensity drift based on displacement curve is put forward, and the effectiveness of the method is verified by grating phase contrast imaging experiment. 3. absorption grating optimized placement of imaging system: in order to reduce the thermal vibration and damage of grating, based on the characteristics of grating structure and material, two kinds of grating placement schemes of normal incidence and back incidence were analyzed and compared. The calculation and experiment show that the two schemes are consistent in the imaging results, but the back incident can reduce the grating vibration and deformation caused by the corresponding thermal effects, improve the stability of the system and prolong the service life of the grating. Grating imaging detector 4. improved calibration scheme: in order to simplify the complex operation of the existing detector calibration process, a grating and light source as a whole in the detector gain correction correction method, and the feasibility of the scheme is verified by experiment. Further, the influence of dark current and gain correction on three information is further analyzed theoretically. A new correction method of grating phase contrast imaging detector is proposed, which only needs dark current correction. The experiment shows that the new scheme is consistent with the existing methods, and can greatly simplify the operation process and improve the efficiency and stability of the system. 5. biomedical imaging and food detection application: a new type of bone mineral density measurement method combining absorption and refraction and through the theoretical calculation and experimental verified; grating imaging results based on crucian carp, found and verified in the sample processing method on the experimental results of different phase contrast imaging; finally, in common Huangmei and Cherry Tomatoes as the sample, to explore the phase contrast imaging in food detection potential.
【學(xué)位授予單位】：中國科學(xué)技術(shù)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：O434.19

【參考文獻】

相關(guān)期刊論文 前3條

1 ;In-line X-ray phase-contrast imaging of murine liver microvasculature ex vivo[J];Nuclear Science and Techniques;2012年01期

2 朱佩平;吳自玉;;X射線相位襯度成像[J];物理;2007年06期

3 茍量,王緒本,曹輝;X射線成像技術(shù)的發(fā)展現(xiàn)狀和趨勢[J];成都理工學(xué)院學(xué)報;2002年02期

相關(guān)博士學(xué)位論文 前2條

1 王圣浩;X射線光柵相位襯度成像技術(shù)和方法研究[D];中國科學(xué)技術(shù)大學(xué);2015年

2 吳朝;X射線光柵相襯成像中的信息分離以及計算機斷層重建[D];中國科學(xué)技術(shù)大學(xué);2014年

相關(guān)碩士學(xué)位論文 前1條

1 張燦;X射線光柵相位襯度成像實驗方法及光柵相關(guān)研究[D];中國科學(xué)技術(shù)大學(xué);2016年

，

本文編號：1339097